5YL3
Crystal structure of horse heart myoglobin reconstituted with manganese porphycene in resting state at pH 8.5
Summary for 5YL3
| Entry DOI | 10.2210/pdb5yl3/pdb |
| Descriptor | Myoglobin, PORPHYCENE CONTAINING MN, SULFATE ION, ... (4 entities in total) |
| Functional Keywords | globin fold, oxygen transport, muscles, oxygen storage |
| Biological source | Equus caballus (Horse) |
| Total number of polymer chains | 1 |
| Total formula weight | 18022.51 |
| Authors | Oohora, K.,Meichin, H.,Kihira, Y.,Sugimoto, H.,Shiro, Y.,Hayashi, T. (deposition date: 2017-10-17, release date: 2017-12-27, Last modification date: 2023-11-22) |
| Primary citation | Oohora, K.,Meichin, H.,Kihira, Y.,Sugimoto, H.,Shiro, Y.,Hayashi, T. Manganese(V) Porphycene Complex Responsible for Inert C-H Bond Hydroxylation in a Myoglobin Matrix. J. Am. Chem. Soc., 139:18460-18463, 2017 Cited by PubMed Abstract: A mechanistic study of HO-dependent C-H bond hydroxylation by myoglobin reconstituted with a manganese porphycene was carried out. The X-ray crystal structure of the reconstituted protein obtained at 1.5 Å resolution reveals tight incorporation of the complex into the myoglobin matrix at pH 8.5, the optimized pH value for the highest turnover number of hydroxylation of ethylbenzene. The protein generates a spectroscopically detectable two-electron oxidative intermediate in a reaction with peracid, which has a half-life up to 38 s at 10 °C. Electron paramagnetic resonance spectra of the intermediate with perpendicular and parallel modes are silent, indicating formation of a low-spin Mn-oxo species. In addition, the Mn-oxo species is capable of promoting the hydroxylation of sodium 4-ethylbenzenesulfonate under single turnover conditions with an apparent second-order rate constant of 2.0 M s at 25 °C. Furthermore, the higher bond dissociation enthalpy of the substrate decreases the rate constant, in support of the proposal that the H-abstraction is one of the rate-limiting steps. The present engineered myoglobin serves as an artificial metalloenzyme for inert C-H bond activation via a high-valent metal species similar to the species employed by native monooxygenases such as cytochrome P450. PubMed: 29237270DOI: 10.1021/jacs.7b11288 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.5 Å) |
Structure validation
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